Chris Haniff edited untitled.tex  about 8 years ago

Commit id: cb193fb68de22558d319e27300d33f65983550e7

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\begin{enumerate}  \item when a new beam train is installed or configured, the AAS must allow for coarse (and possibly manual) alignment of the beam train to allow an alignment beam to pass between the beam combining area (BCA) and the unit telescope mount (UTM) without vignetting;  \item at the beginning of each observing night, the AAS must re-align the beam train so that beams of starlight arriving at the beam combiners meet the tilt and shear error budget;  \item during the night, the AAS must make fine adjustments to the alignment so that the tilt and shear error budget is maintained in the presence of thermal drifts, typically introduced by those  optics located  in temperature unstable environments; \item when a new beam train is installed or configured, the AAS must allow for measurement of the "piston" term due to the optical path between the beam combiners and the telescopes, in order to allow for rapid acquisition of stellar fringes;  \item at the beginning of the night, the AAS must allow the pathlength differences between the fringe tracker and the science instrument to be measured so that these can be equalized.  \end{enumerate}